This maximum frequency can be found in several ways [1]}, [2]}, but its fundamental essence is shown above to be ultimately the same: this is the reciprocal of the minimum window within which two successive configurations cannot be distinguished.
Whenever the favorable spatial configuration reappears, the reaction is possible but not necessarily achieved. It proceeds only when a second condition, energetic, is fulfilled simultaneously. Reciprocally, when the required energy level is reached, no reaction will occur if the configuration is not permissive at the same time. The dimensionless part of the constants is therefore the product of two independent probabilities. The second one, the energetic probability, is the exponential factor of Arrhenius.
